The cleaved products of castor oil and its derivatives have several useful applications. For example, one cleaved product, sodium sebacate, is a precursor to sebacic acid. Sebacic acid is extremely valuable in the production of nylon 610 and alkyds. Unfortunately, complications associated with the commercial production of such cleaved products often make the process costly and wasteful.
Presently, these cleaved products are generally produced by the high temperature caustic oxidation of castor oil in the presence of a strong alkali and a catalyst. Several problems plague this production method. First, when the castor oil or derivative is treated with alkali or caustic, the reaction mixture has a tendency to foam violently and/or the reactants tend to solidify. These complications typically hinder, or even stop, the ongoing oxidation reaction. Furthermore, the hard alkaline soap formed when the reactants solidify poses additional problems, since it is a poor conductor of heat and makes the reactants difficult to mix by mechanical agitation.
There exist alternative methods of producing such cleaved products, but they are often hampered by high production costs. Certain references which disclose the production of cleaved products of castor oil and its derivatives are discussed below.
U.S. Pat. No. 4,786,666 discloses a process for making epoxy esters from epoxy resins and fatty acids, wherein the epoxy resin is made from a diglycidyl ether of a dihydric phenol and castor oil polyglycidyl ether reacted with a dihydric phenol. The castor oil polyglycidyl ether is prepared by reacting castor oil and epichlorohydrin using a Lewis acid catalyst and dihydrohalogenating the chlorohydrin adduct with a caustic agent.
U.S. Pat. No. 4,574,053 discloses a soap bar filled with particulate inorganic filler materials that are coated with fatty acid that has chemically reacted with the filler. The fatty acid used in the soap base may be castor oil.
U.S. Pat. No. 4,299,976 discloses a process for producing an unsaturated diester useful as a precursor for sebacic acid, which is produced by contacting methyl penta-2,4-dienoate at 30 to 150.degree. C. under an inert atmosphere with a catalytic amount of a homogeneous palladium complex. This patent also discloses several processes for preparing sebacic acid, including an existing commercial process using castor oil. That process is accomplished by caustic decomposition of ricinoleic acid at 245.degree. C. to yield disodium sebacate acid, followed by hydrolysis of the disodium sebacate, to produce sebacic acid.
U.S. Pat. No. 4,298,737 discloses the synthesis of piperidinyl substituted 1,4-diaza-2-cycloalkanones and substituted derivatives thereof by combining a piperidinyl substituted diamine and a suitable co-reactant in the presence of a phase transfer catalyst and caustic, for use as UV stabilizers in photodegradable plastics. The caustic agent retards formation of the desired product and thereby helps control the exothermic reaction. Castor oil may be added to the stabilized polymer as an optional ingredient.
U.S. Pat. No. 4,251,451 discloses a process for reacting a mixture of branched and linear alcohols with a caustic to produce a reaction mixture containing carboxylic acid salts and to liberate hydrogen by adding an inert diluent that reduces the tendency of the reaction mixture to foam and solidify. Sufficient diluent is added at a particular time in the reaction, before hydrogen release but after the reaction has begun, to inhibit foam formation and solidification of the reaction mixture, while maintaining fluidity of the reaction mixture to allow passage of liberated hydrogen. Furthermore, this reference does not disclose the use of the recited process in the oxidation of castor oil or its derivatives.
U.S. Pat. No. 3,671,581 discloses a process for the production of carboxylic acids by reacting a starting material, one of which is the non-acidic by-product obtained from the oxidation of castor oil to produce sebacic acid, with fused alkali metal hydroxide at a temperature of between 250 to 375.degree. C.
U.S. Pat. No. 3,668,092 discloses a process for bleaching carboxylic acid esters, such as castor oil, or epoxy compounds, by irradiating them with UV light in the presence of a peroxy compound. A similar prior process involved treatment with a caustic.
None of these references disclose how to reduce the foaming and/or solidification that has hindered the previous oxidation of castor oil and/or derivatives thereof. It would be desirable to produce cleaved products of castor oil and or its derivatives while reducing the foaming and/or solidification to raise product yield and purity.